class_docstr: For test code - build a dummy ResponseObservation proto.
code: def game_loop(self, game_loop):
      self._game_loop = game_loop
      return self
  
imports: import math
  import numpy
  from pysc2.lib import features
  from s2clientprotocol import raw_pb2
  from s2clientprotocol import sc2api_pb2
  from s2clientprotocol import score_pb2
label_desc: Use image node_id 2 for calling the Builder obj's underlying member method code with example usage: obj.game_loop(game_loop) and returns: self